Creation of Multi‐Principal Element Alloy NiCoCr Nanostructures via Nanosecond Laser‐Induced Dewetting

Abstract

AbstractThe multi‐principal element alloy nanoparticles (MPEA NPs), a new class of nanomaterials, present a highly rewarding opportunity to explore new or vastly different functional properties than the traditional mono/bi/multimetallic nanostructures due to their unique characteristics of atomic‐level homogeneous mixing of constituent elements in the nanoconfinements. Here, the successful creation of NiCoCr nanoparticles, a well‐known MPEA system is reported, using ultrafast nanosecond laser‐induced dewetting of alloy thin films. Nanoparticle formation occurs by spontaneously breaking the energetically unstable thin films in a melt state under laser‐induced hydrodynamic instability and subsequently accumulating in a droplet shape via surface energy minimization. While NiCoCr alloy shows a stark contrast in physical properties compared to individual metallic constituents, i.e., Ni, Co, and Cr, yet the transient nature of the laser‐driven process facilitates a homogeneous distribution of the constituents (Ni, Co, and Cr) in the nanoparticles. Using high‐resolution chemical analysis and scanning nanodiffraction, the environmental stability and grain arrangement in the nanoparticles are further investigated. Thermal transport simulations reveal that the ultrashort (≈100 ns) melt‐state lifetime of NiCoCr during the dewetting event helps retain the constituent elements in a single‐phase solid solution with homogenous distribution and opens the pathway to create the unique MPEA nanoparticles with laser‐induced dewetting process.